This invention relates to a reservoir tank which is structured to be mounted on a master cylinder or a hydraulic pressure booster in a vehicle brake system.
FIG. 10 shows a conventional reservoir tank of this type which is disclosed in unexamined JP patent publication 10-35469. This reservoir tank, generally designated 110, comprises a tank body 111 made of a synthetic resin, and mounted on a master cylinder 1 with its ports 112 and 114 connected to corresponding ports of the master cylinder 1. The body 111 has a hydraulic fluid supply port 113 in its top through which hydraulic fluid a is supplied into the tank 110. Through the ports 112, hydraulic fluid flows between the reservoir and the master cylinder. Through the ports 114, hydraulic fluid a is supplied to the master cylinder 1 and/or hydraulic units such as pumps. Numeral 115a designates a strainer.
JP patent publication 06-156254 discloses a similar reservoir tank of which the interior is divided into a first fluid chamber and a second fluid chamber, with the inlet/outlet port 112 and the hydraulic fluid supply port 113 communicating with the first fluid chamber and the outlet ports 114 communicating with the second fluid chamber.
Because this type of reservoir tank is installed in a narrow, limited space in a vehicle engine room, its mounting position is limited. That is, in most cases, it has to be mounted with the hydraulic fluid supply port 113 facing upward.
Component parts of this type of vehicle brake system have to be frequently replaced or removed for repair. After such replacement or repair, air has to be expelled from the brake system. This is done by pumping the brake pedal with the cap 115 of the hydraulic fluid supply port 113 removed to mount a brake fluid injector or a brake fluid can on the reservoir tank 110.
When pumping the brake pedal, hydraulic fluid a tends to gush into the reservoir tank through the inlet/out let port 112. As shown, the ports 112 and 113 directly face each other. Thus, hydraulic fluid rushing into the reservoir tank tends to be blown out through the port 113. Hydraulic fluid blown out through the port 113 may find its way into an operator's eye or stain clothes. This causes deterioration in the work environment and health hazard.
An object of the invention is to provide a reservoir tank having means for preventing hydraulic fluid from being blown out through the hydraulic fluid supply port even when this port is open.